- Consumption of more than 1000 IU vitamin D/day in the 36 months prior to enrollment, or a bolus of 300'000 IU or more in the last 12 month prior to enrollment, and/ or unwillingness to limit vitamin D intake to the current standard of 800 IU/day of vitamin D during the course of the trial. Provision 1: an individual who consumed an average vitamin D dose between 1000 and 2000 IU vitamin D/day in the 3 months prior to enrollment, may be enrolled after a 3-month wash-out period where the maximum daily intake is limited to 800 IU vitamin D. Provision 2: an individual who consumed an average vitamin D dose higher than 2000 IU/day in the 3 months prior to enrollment, may be enrolled after a 6-month wash-out period where the maximum daily intake is limited to 800 IU vitamin D.